As the competition in the feed market becomes increasingly fierce, the quality of pellet feed has received more and more attention. Users require that feed pellets have a smooth appearance, uniform pellets, appropriate pellet hardness, low pulverization rate, and moisture content that meets standards. The realization of these requirements involves many aspects such as feed formula and raw material quality, feed processing technology, and equipment.

Influence of feed formula and raw material quality

Feed formulation and raw material quality have a great impact on pellet quality. The formula contains energy feed, protein feed, mineral feed and additive premixed feed, which are 60%~70%, 20%~25%, 3%~5%, and 1%~2% respectively. Energy feed and protein feed are the main components and the main factors affecting grain quality.

1 Diversity of raw materials

Currently, in order to reduce costs, there are more and more alternative raw materials, such as wheat and rice bran. DDG, brewer’s grains, corn gluten meal, bacterial protein, yeast, rapeseed meal, cottonseed meal, blood meal, meat (bone) meal, silkworm meal, etc. Due to the large difference in quality of these alternative raw materials, the ability of the feed to absorb steam is reduced, which is manifested by loose particles, dull surface, poor hardness, and high pulverization rate.

In order to improve the quality of granules, it is often necessary to add ingredients that increase cohesion in the formula, such as wheat, ice flour or bentonite clay. According to our usage, adding an appropriate amount of wheat or sub-flour is more effective, mainly because it is rich in gluten protein and soluble fiber, which is easier to absorb steam and mature, thereby improving the quality of the particles.

2 Protein content

Protein content is an important factor in determining the quality of pellets. Generally speaking, when the protein content in the formula is higher, it is easier to granulate and the pellet quality is better, because the plasticity and viscosity of the protein increase after heating, which increases the granulation yield and good quality. .

But when the protein content in the formula is too high, the granulation effect decreases. 30% of the concentrated feed for laying hens (excluding corn and flour, etc.) is pelleted. Due to the low starch content, crude fiber content of more than 12%, and crude protein content of more than 35%, its ability to absorb steam is seriously reduced. , the feed conditioning temperature is only 50~6 0°C, and the quality of the pellets is seriously reduced.

3 Cellulose content

The crude fiber content in the feed should not exceed 10%, because the fiber itself has poor cohesion, which reduces the binding force between feed particles and also affects the ability of the feed to absorb steam, thereby reducing the hardness, forming rate and yield of the feed particles. The wear and tear of granulation equipment has increased seriously.

4 Fat content

If an appropriate amount of fat is added to the feed, the fluidity of the feed through the die hole will be good, the friction resistance will be reduced, the feed will be easy to form, and the ring die of the granulator will have less wear, low energy consumption, and good pellet quality. However, if the fat content in the feed is too high, the quality of the pellets will decrease instead. Because fat can reduce the binding force between feed particles, the pellets will easily break, making it difficult to store electricity. When excess fat is needed in the feed, it can be added by spraying after pelleting.

5 Moisture content

Generally speaking, when the moisture content of feed before conditioning is less than 12.5%, its ability to absorb steam is strong, the conditioning temperature is high, and the pellet quality is good. According to many years of practice, the effect is best when the moisture content of powdered feed after conditioning is 15.5%~17%. According to general rules, when the temperature of powdered feed increases by 10°C, the moisture content increases by approximately 0.6%. The temperature required for starch to smelt is 80°C. Therefore, the moisture content of starch feed before conditioning should not be too high. , otherwise its ability to absorb steam will decrease, the conditioning temperature of powdered feed will decrease, the degree of starch smelt and protein denaturation will decrease, the bonding force between feed particles will decrease, and the quality of the particles will decrease.

In recent years, every time new corn comes on the market, it is difficult to add steam when conditioning the feed, and the power consumption of pelleting production is high. The productivity is low, the hardness of the feed particles is poor, and the powdering rate is high. In view of the above situation, we temporarily stored the powdered feed in the pelleting intermediate warehouse for 16 to 24 hours to allow sufficient mass transfer between the feed materials, and then granulated it. After production assessment, we found that the feed’s ability to absorb steam increased and the conditioning temperature was basically the same. Guaranteed above 70°C.

6 Hygroscopicity of raw materials

When there are highly hygroscopic raw materials in powdered feed, if the production preparation time is long, the fluidity of the powdered feed will be seriously reduced. At the same time, this type of feed has poor pelleting performance and poor pellet quality.

For example, when producing suckling pig feed, raw materials such as citric acid whey powder and milk replacer powder are added. Since these raw materials easily become sticky when exposed to air and easily coke when exposed to high temperatures, it is particularly difficult to add steam during granulation and conditioning. The temperature is low and the particle quality is poor. When producing this kind of feed, only the method of rapid production with less steam can be used.